Question

The wild-type form of a gene encodes a protein of length 100 amino acids. A mutant allele has a UAA (instead of the wild-type, CAA) at the 49th codon in the gene. How long is the protein product made from the mutant form of the gene?

Answer 1

48 amino acids

Step-by-step explanation:

The wild type gene codes for a protein with 100 amino acids. One amino acid is encoded by one triplet code of the gene. This means that the wild type gene has a total 100 triplets or 300 nucleotides to code for a protein of 100 amino acid. Mutation in this protein has introduced the code "UAA" at the 49th codon. The code "UAA" is a stop codon. Therefore, the mRNA transcribed from the mutant allele would code for a protein having 48 amino acids as the protein synthesis will be stopped once the stop codon at the 49th position is read.